The name Mercury is connected with the root merx (merchandise) and mercari (to deal, trade). The early Romans, being above all countrymen, had no need for a god of commerce. The Roman Mercury appeared only about the fifth century BCE. and was exclusively the god of merchants. For long he was known only in this capacity. so that Plautus. in his prologue to Amphitryon, reminds his audience that Mercury presided over messages and commerce. Like certain other minor divinities - Pecunia, Aesculanus, Argentinus - he watched over tradesmen's profits.
Mercury had a temple on the Aventine. Among animals the cock was especially sacred to him.
To portray him Roman artists generally drew upon representations of Hermes. They gave Mercury a beardless face and. for attributes. the caduceus and the winged petasus, with a purse in his hand.
Hermes, the Mercury of the Romans; in the Greek mythology the herald of the gods and the god of eloquence and of all kinds of cunning and dexterity in word and action; invented the lyre, the alphabet, numbers, astronomy, music, the cultivation of the olive, etc.; was the son of Zeus and Maia; wore on embassy a winged cap, winged sandals, and carried a herald's wand as symbol of his office.